How are the mind and body related?
They are related to the central nervous system and peripheral nervous system.
In science, it is known that left hemisphere of cerebrum commands to the right part of the body and vice versa.
the central nervous system is consisted out of brain (cerebrum, cerebellum, etc.) and spinal cord. Together, they coordinate with incoming and outgoing signals. The greater function would be thinking and learning.
The example for the peripheral nervous system would be a skeletal muscle and a muscle of a bladder. You can control skeletal muscles; however you cannot control the muscle of the bladder. The peripheral nervous system has two branches: (1) somatic, and (2) autonomic. Furthermore, the autonomic is divided into parasympathetic and sympathetic.
The somatic would be voluntary (e.g. skeletal muscle), whereas autonomic would be involuntary (e.g. muscle of the baldder). The parasympathetic and sympathetic autonomic nervous systems maintain the homeostasis on a level of organs. For example, if sympathetic ANS stimulates the heart to beat faster the parasympathetic ANS tries to normalize it.